A wideband metamaterial-inspired compact antenna using embedded non-Foster matching

Passive electrically small antennas have a small radiation resistance and a narrow bandwidth. In this paper, a new type of active antenna is reported in which an active circuit generating a non-Foster impedance is embedded in a metamaterial-inspired small antenna with an inherent sizable radiation resistance. This circuit interacts with the reactive elements of the antenna. The end result is a compact, broadband antenna which is well matched and has the potential for a high efficiency. In this process, the need for an active (or passive) step-up transformer for the radiation resistance is eliminated. This work opens up the possibility of utilizing non-Foster components embedded in metamaterial-based antenna structures to obtain efficient antennas by manipulating the current and field distribution in and around the antenna.